1. Field of the Invention
The present invention relates generally to valve mechanisms and ink cartridges comprising such valve mechanisms.
2. Description of Related Art
A known ink-jet image recording apparatus has a recording head and an ink supply device configured to supply ink to the recording head. A known ink cartridge is configured to be mounted to the ink supply device. The known ink cartridge has a case, and the case has an ink chamber formed therein. The ink chamber is configured to store ink therein. The case has an ink supply portion, and ink is supplied from an interior of the ink chamber to an exterior of the ink chamber via the ink supply portion. When the known ink cartridge is mounted to the ink supply device, ink stored in the ink chamber is supplied to the recording head via the ink supply portion. The recording head is configured to selectively eject ink toward a sheet of paper, such that an image is recorded on the sheet. The known ink cartridge also has a check valve positioned adjacent to the ink supply portion, and the check valve is configured to prevent ink from returning from the recording head to the ink chamber.
Another known ink cartridge, such as the ink cartridge described in JP-A-2007-144808, has an ink supply portion. The interior of the ink supply portion is partitioned from an ink chamber by a particular wall. The particular wall has an opening formed therethrough, and the interior of the ink supply portion is configured to be in fluid communication with the ink chamber via the opening of the particular wall. The another known ink cartridge also has a check valve element and a cover positioned in the interior of the ink supply portion. The check valve element has a substantially umbrella shape, and has a canopy portion and a handle portion. The cover has a first opening formed therethrough and a plurality of second openings formed therethrough. The handle portion is inserted through the first opening, and the second openings are configured to allow ink to flow therethrough. The cover contacts the particular wall. When the pressure in the ink chamber is greater than the pressure in the interior of the ink supply portion, the canopy portion receives a pressure from ink, and the check valve element moves, such that the canopy portion moves away from the cover. Because the second openings are uncovered, the ink flows from the ink chamber to the interior of the ink supply portion. In contrast, when the pressure in the ink chamber is less than the pressure in the interior of the ink supply portion, the canopy portion receives a pressure from ink, and the check valve element moves, such that the canopy portion moves toward the cover. Accordingly, the second openings are closed by the canopy portion, and the flow of ink from the interior of the ink supply portion toward the ink chamber is prevented.
Nevertheless, when the check valve element moves, the handle portion receives a resistance from the cover because the handle slides on the cover in the first opening. Therefore, when the amount of ink flow is relatively small, e.g., when the pressure differential between the ink chamber and the interior of the ink supply portion is relatively small, the check valve element may not move properly.